Silicone resin composition, curable resin composition, and curable resin

ABSTRACT

The present invention relates to a silicone resin composition of low melt viscosity and excellent reactivity and dispersibility in organic resins. The present invention also relates to a curable resin composition for forming a cured resin of excellent moldability and superior flame retardant properties while having little adverse impact on the human body and the environment as a result of containing no antimony oxides or halogenated epoxy resins. The present invention also relates to a cured resin having little adverse impact on the human body or the environment and possessing superior flame retardant properties.

TECHNICAL FIELD

The present invention relates to a silicone resin composition of lowmelt viscosity and excellent reactivity and dispersibility in organicresins. The present invention also relates to a curable resincomposition for forming a cured resin of excellent moldability andsuperior flame retardant properties while having little adverse impacton the human body and the environment as a result of containing noantimony oxides or halogenated epoxy resins. The present invention alsorelates to a cured resin having little adverse impact on the human bodyor the environment and possessing superior flame retardant properties.

BACKGROUND ART

As disclosed in Japanese Unexamined Patent Application Publication No.Hei 6-298940, it is possible to prepare silicone resins having anyarbitrary molecular weight, softening point, or glass transition pointsdepending on the reaction conditions and the combination of siloxanes orsilanes used as the starting materials, however, regulating their meltviscosity and their reactivity and dispersibility in mixtures withorganic resins has been a tough problem.

On the other hand, although curable resin compositions can produce curedresin of superior dielectric characteristics, volume resistivity,dielectric breakdown strength, and other electrical characteristics, aswell as flexural strength, compression strength, impact strength, andother mechanical characteristics, in order to improve their flameretardant properties, they have to be combined with halogen-containingcompounds and antimony oxides, such as antimony trioxide, which givescause for concern with respect to their impact on the human body and theenvironment due to the toxicity of the antimony oxide powders and thetoxic gases released during the burning of the resultant cured resins.

In accordance with the teachings of Japanese Unexamined PatentApplication Publication No. Hei 6-298897, combining silicone resins withcurable resins improves pre-curing flowability and provides for betterflexibility, moisture resistance, and resistance to thermal shock. Inaddition, in accordance with the teachings of Japanese Unexamined PatentApplication Publication No. Hei 11-222559 and Japanese Unexamined PatentApplication Publication No. Hei 11-323086, etc., combining siliconeresins with curable resins improves the flame retardant properties ofthe cured resin. However, the problem with the curable resin compositiondisclosed in Japanese Unexamined Patent Application Publication No. Hei6-298897 was the insufficient flame retardant properties of theresultant cured resin. The problem with the curable resin compositionsdisclosed in Japanese Unexamined Patent Application Publication No. Hei11-222559 and Japanese Unexamined Patent Application Publication No. Hei11-323086 was poor moldability causing mold contamination duringmolding, etc.

It is an object of the present invention to provide a silicone resincomposition of low melt viscosity and excellent reactivity anddispersibility in organic resins, a curable resin composition forming acured resin of excellent moldability and superior flame retardantproperties and having little adverse impact on the human body and theenvironment as a result of containing no antimony oxides or halogenatedepoxy resins, as well as a cured resin having little adverse impact onthe human body or the environment and possessing superior flameretardant properties.

DISCLOSURE OF INVENTION

One embodiment of the present invention comprises a silicone resincomposition comprising (A) a silicone resin with a softening pointexceeding 25° C., and (B) a silicone resin that is liquid at 25° C.Other embodiments of the present invention include a curable resincomprising: (I) a curable resin, (II) a silicone resin with a softeningpoint exceeding 25° C., and (III) a silicone resin that is liquid at 25°C. and the cured resin obtained by curing the above-mentioned curableresin composition.

One embodiment of the present invention is a silicone resin compositioncomprising:

-   -   (A) a silicone resin with a softening point exceeding 25° C.,        represented by the average unit formula:        (R¹SiO_(3/2))_(a)(R² ₂SiO_(2/2))_(b)(R³        ₃SiO_(1/2))_(c)(SiO_(4/2))_(d)(XO_(1/2))_(e)        where R¹, R², and R³ stand for identical or different monovalent        hydrocarbon groups or epoxy-containing organic groups such that,        of the total number of R¹, R², and R³ groups in the molecule,        0.1 to 40 mol % comprises epoxy-containing organic groups and        not less than 10 mol % comprises phenyl groups, X is a hydrogen        atom or alkyl group, a is a positive number, b is 0 or a        positive number, c is 0 or a positive number, d is 0 or a        positive number, and e is 0 or a positive number such that b/a        is a number from 0 to 10, c/a is a number from 0 to 0.5,        d/(a+b+c+d) is a number from 0 to 0.3, and e/(a+b+c+d) is a        number from 0 to 0.4, and    -   (B) a silicone resin that is liquid at 25° C.

DETAILED DESCRIPTION OF THE INVENTION

Component (A) is a silicone resin with a softening point exceeding 25°C., represented by the average unit formula (R¹SiO_(3/2))_(a)(R²₂SiO_(2/2))_(b)(R³ ₃SiO_(1/2))_(c)(SiO_(4/2))_(d)(XO_(1/2))_(e). In theformula above, R¹, R², and R³ stand for identical or differentmonovalent hydrocarbon groups or epoxy-containing organic groups. Themonovalent hydrocarbon groups are exemplified by methyl, ethyl, propyl,butyl, pentyl, hexyl, heptyl, and other alkyl groups; vinyl, allyl,butenyl, heptenyl, hexenyl, and other alkenyl groups; phenyl, tolyl,xylyl, naphthyl, and other aryl groups; benzyl, phenetyl, and otheraralkyl groups; chloromethyl, 3-chloropropyl, 3,3,3-trifluoropropyl,nonafluorobutylethyl, and other substituted alkyl groups. In addition,the epoxy-containing organic groups are exemplified by 2,3-epoxypropyl,3,4-epoxybutyl, 4,5-epoxypentyl, and other epoxyalkyl groups;2-glycidoxyethyl, 3-glycidoxypropyl, 4-glycidoxybutyl, and otherglycidoxyalkyl groups; 2-(3,4-epoxycyclohexyl)ethyl,3-(3,4-epoxycyclohexyl)propyl, and other epoxycyclohexylalkyl groups.

Of the total number of R¹, R², and R³ groups in the molecule, 0.1 to 40mol % comprises epoxy-containing organic groups. This is due to the factthat when the content of the epoxy-containing organic groups is belowthe lower end of the above-mentioned range, combining the resultantsilicone resin composition with organic resins results in bleedingduring the molding of the organic resin composition and the flexibility,moisture resistance, and thermal shock resistance of the obtainedmoldings have a tendency to decrease while, on the other hand, when thecontent exceeds the upper end of the above-mentioned range, themechanical characteristics of the resultant moldings tend to decrease.

In addition, due to their superior affinity for organic resins, not lessthan 10 mol % of the total number of R¹, R², and R³ groups comprisephenyl groups. In particular, preferably, phenyl groups should comprisenot less than 10 mol % of R¹, and even more preferably, phenyl groupsshould comprise not less than 30 mol % of R¹.

In the formula above, X stands for a hydrogen atom or alkyl groups, withthe alkyl groups exemplified by methyl, ethyl, propyl, butyl, pentyl,hexyl, and heptyl.

In the formula above, subscript a is a positive number, subscript b is 0or a positive number, subscript c is 0 or a positive number, subscript dis 0 or a positive number, and subscript e is 0 or a positive numbersuch that b/a is a number from 0 to 10, c/a is a number from 0 to 0.5,d/(a+b+c+d) is a number from 0 to 0.3, and e/(a+b+c+d) is a number from0 to 0.4. This is due to the fact that the softening point of a siliconeresin with ab/a exceeding 10 may drop below 25° C. and its affinity fororganic resins may also decrease. In addition, a silicone resin with ac/(a+b+c) exceeding 0.3 has a tendency toward decreased dispersibilityin organic resins.

There are no limitations concerning the weight-average molecular weightof component (A). Preferably, however, it should be in the range of from500 to 50,000, and more preferably, in the range of from 500 to 10,000.In addition, although there are no particular limitations if thesoftening point of component (A) exceeds 25° C., preferably, it shouldbe in the range of from 40 to 250° C. and more preferably, in the rangeof from 40 to 150° C. This is due to the fact that silicone resin with asoftening point below the lower end of the range bleeds during themolding of the organic resin, with which it is combined, therebycontaminating the mold, and tends to decrease the mechanicalcharacteristics of the moldings. On the other hand, silicone resin witha softening point exceeding the upper end of the range exhibits atendency towards increased difficulty of uniform dispersion in organicresins.

Although there are no limitations concerning the method used for thepreparation of the silicone resin of component (A), it is preferable touse a method, in which a mixture of one, two, or more siloxanes orsilanes having at least one unit selected from the group comprising (A′)(i) units represented by the formula R⁴SiO_(3/2), where R⁴ is amonovalent hydrocarbon group, (ii) units represented by the formula R⁵₂SiO_(3/2), where R⁵ stands for identical or different monovalenthydrocarbon groups, (iii) units represented by the formula R⁶₃SiO_(1/2), where R⁶ stands for identical or different monovalenthydrocarbon groups, and (iv) units represented by the formula SiO_(4/2)is reacted with (A″) an epoxy-containing alkoxysilane, or a partialhydrolysis product thereof, represented by the general formula: R⁷R⁸_(f)Si(OR⁹)_((3-f)), where R⁷ is an epoxy-containing organic group, R⁸is a monovalent hydrocarbon group, R⁹ is an alkyl group, and subscript fis 0, 1, or 2, in the presence of a basic catalyst.

In the above-described method of preparation, component (A′) is theprimary raw material, i.e. a mixture of one, two, or more siloxanes orsilanes having at least one unit selected from the group comprisingunits represented by the formulas (i)-(iv) above. Component (A′) isexemplified by siloxanes or silanes consisting only of the unitsrepresented by (i), siloxanes or silanes consisting only of the unitsrepresented by (ii), siloxanes or silanes consisting only of the unitsrepresented by (iii), siloxanes or silanes consisting only of the unitsrepresented by (iv), siloxanes consisting of units represented by (i)and units represented by (ii), siloxanes consisting of units representedby (i) and units represented by (iii), siloxanes consisting of unitsrepresented by (i) and units represented by (iv), siloxanes consistingof units represented by (i), units represented by (ii), and unitsrepresented by (iii), siloxanes consisting of units represented by (i),units represented by (ii), and units represented by (iv), and siloxanesconsisting of units represented by (i), units represented by (ii), unitsrepresented by (iii), and units represented by (iv). In addition, R⁴,R⁵, and R⁶ in the formula above are identical or different monovalenthydrocarbon groups, exemplified by the same monovalent hydrocarbongroups as the above-mentioned R¹, R², or R³. Preferably, phenyl groupsshould constitute not less than 10 mol % of R⁴ and more preferably,phenyl groups should constitute not less than 30 mol % of R⁴.

The silanes or siloxanes of component (A′) are exemplified bymethyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane,ethyltriethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane,3,3,3-trifluoropropyltrimethoxysilane, dimethyldimethoxysilane,methylphenyldimethoxysilane, methylvinyldimethoxysilane,diphenyldimethoxysilane, dimethyldiethoxysilane,methylphenyldiethoxysilane, tetramethoxysilane, tetraethoxysilane,tetrapropoxysilane, dimethoxydiethoxysilane, and products of theirhydrolysis and condensation.

In the above-mentioned method of preparation, component (A″) is anepoxy-containing alkoxysilane, or a partial hydrolysis product thereof,represented by the general formula R⁷R⁸ _(f)Si(OR⁹)_((3-f)). In theformula above, R⁷ is an epoxy-containing organic group, exemplified bythe same epoxy-containing organic groups as the above-described R¹, R²,or R³. The group R⁸ in the formula above is a monovalent hydrocarbongroup, exemplified by the same monovalent hydrocarbon groups as theabove-described R¹, R², or R³. The group R⁹ in the formula above is analkyl group, exemplified by methyl, ethyl, propyl, butyl, pentyl, hexyl,and heptyl. Subscript f is 0, 1, or 2, preferably, 0.

The epoxy-containing alkoxysilanes are exemplified by3-glycidoxypropyl(methyl)dimethoxysilane,3-glycidoxypropyl(methyl)diethoxysilane,3-glycidoxypropyl(methyl)dibutoxysilane,2-(3,4-epoxycyclohexyl)ethyl(methyl)dimethoxysilane,2-(3,4-epoxycyclohexyl)ethyl(phenyl)diethoxysilane,2,3-epoxypropyl(methyl)dimethoxysilane,2,3-epoxypropyl(phenyl)dimethoxysilane,3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane,3-glycidoxypropyltributoxysilane,2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,2-(3,4-epoxycyclohexyl)ethyltriethoxysilane,2,3-epoxypropyltrimethoxysilane, and 2,3-epoxypropyltriethoxysilane.

In the above-described method of preparation, component (A′) is reactedwith component (A″) in the presence of a basic catalyst. The basiccatalyst is a catalyst used in the co-hydrolysis, condensation reactionand equilibration reaction of component (A′) and component (A″). Forinstance, one may suggest using sodium hydroxide, potassium hydroxide,cerium hydroxide, and other hydroxides of alkali metals; sodiumt-butoxide, potassium t-butoxide, cerium t-butoxide, and other alkoxidesof alkali metals; sodium silanolate compounds, potassium silanolatecompounds, cerium silanolate compounds, and other silanolate compoundsof alkali metals, with potassium- or cerium-based basic catalysts beingpreferable. Water may be added if needed for the reaction ofco-hydrolysis and condensation of component (A′) and component (A″). Inaddition, after reacting component (A′) and component (A″), ifnecessary, the concentration of solid matter in the reaction system maybe adjusted using an organic solvent and the reaction may be conductedfurther.

In the above-described method of preparation, the equilibration reactioncauses siloxane bonds to be severed and recombination to take place in arandom fashion, with the resultant epoxy-containing silicone resinequilibrated. The temperature of the reaction should be preferably 80°C. to 200° C. and more preferably, 100° C. to 150° C., because if thereaction temperature is low, then the equilibration reaction does notproceed to a sufficient extent, and if the reaction temperature isexcessively high, the silicon-bonded organic groups undergo thermaldecomposition. In addition, selecting organic solvents with a boilingpoint of 80° C. to 200° C. makes it possible to easily carry out theequilibration reaction at the reflux temperature. In addition, theequilibration reaction can be terminated by neutralizing the basiccatalyst. It is preferable to add carbon dioxide gas, carboxylic acid,or another weak acid to carry out the neutralization. The salts producedas a result of the neutralization can be easily removed by filtration orwashing with water.

Component (B) comprises a silicone resin liquid at 25° C. Component (B)is used to improve the dispersibility of the silicone resin compositionof the present embodiment in organic resins. There are no limitationsconcerning the viscosity of component (B) at 25° C., however,preferably, it should be in the range of from 5 to 100,000 mPa·s andmore preferably, in the range of from 10 to 5,000 mPa·s. In addition,although there are no limitations concerning the number averagemolecular weight of component (B), preferably, as converted to standardpolystyrene, it should be in the range of from 500 to 5,000, and morepreferably, in the range of from 1,000 to 4,000.

There are no limitations concerning the molecular structure of component(B), however, in the same manner as in the case of component (A), it ispreferably a silicone resin having at least one unit selected from thegroup comprising units represented by the formula R¹SiO_(3/2) (T-units),units represented by the formula R² ₂SiO_(2/2) ( )-units), unitsrepresented by the formula R³ ₃SiO_(1/2) (M-units), and unitsrepresented by the formula SiO_(4/2) (Q-units). In addition, component(B) may have silanol groups or silicon-bonded alkoxy groups and otherhydrolyzable groups. Component (B) is represented, for instance, by theaverage unit formula (R¹SiO_(3/2))_(a)(R² ₂SiO_(2/2))_(b)(R³₃SiO_(1/2))_(c)(SiO_(4/2))_(d)(XO_(1/2))_(e). In the formula above, R¹,R², and R³ stand for identical or different monovalent hydrocarbongroups or epoxy-containing organic groups, exemplified by the samegroups as those described above. In addition, in the formula above, X isa hydrogen atom or alkyl group, exemplified by the same groups as thosedescribed above. Also, in the formula above, subscript a is a positivenumber, subscript b is 0 or a positive number, subscript c is 0 or apositive number, subscript d is 0 or a positive number, and thesubscript e is 0 or a positive number such that b/a is a number from 0to 10, c/a is a number from 0 to 0.5, d/(a+b+c+d) is a number from 0 to0.3, and e/(a+b+c+d) is a number from 0 to 1. There are no limitationsconcerning the method of preparing the silicone resin of component (B).It can be prepared by the same method as the one used for theabove-described component (A).

In the silicone resin composition of the present invention, there are nolimitations concerning the content of component (B). It is preferable,however, that the content should be in the range of from 0.15 to 200parts by weight per 100 parts by weight of component (A). This is due tothe fact that if the content of component (B) is lower than the lowerend of the range, there is a possibility that the dispersibility of theresultant silicone resin composition in organic resins may decrease,and, on the other hand, if it exceeds the upper end of the range, thereis a possibility that the moldability of the organic resin containing itmay decrease.

Although there are no limitations concerning the method of preparing thesilicone resin composition of the present invention, suggested methodsinclude a method in which component (A) and component (B) are mixed in amolten state, or a method in which after mixing component (B) with asolution of component (A) in an organic solvent, the organic solvent isremoved. The mixing equipment used at such time is exemplified bysingle-spindle and double-spindle continuous mixers, two roll mills,Ross mixers, kneader-mixers, and mixers equipped with apressure-reducing device allowing for solvent removal. In addition, theorganic solvents are exemplified by toluene, xylene, and other aromatichydrocarbons and by acetone, methylethylketone, and other ketone-basedsolvents.

Although there are no limitations concerning the melt viscosity of thesilicone resin composition of the present invention at 100° C.,preferably it should be not more than 100,000 mPa·s, and more preferablynot more than 10,000 mPa·s. In addition, although there are nolimitations concerning the melt viscosity of the silicone resincomposition of the present invention at 160° C., preferably, it shouldbe not more than 10,000 mPa·s. In addition, it is preferable that thesilicone resin composition of the present invention should be solid at25° C. and its melting point should be in the range of from 40° C. to150° C.

The above-described silicone resin composition of the present inventionis useful as an additive imparting heat resistance, flame resistance,water repellency, etc. to organic resins. Curable resins andthermoplastic resins are suggested as the organic resins, with which thesilicone resin composition of the present invention can be combined,with the curable resins exemplified by phenolic resins, formaldehyderesins, xylene resins, xylene-formaldehyde resins, ketone-formaldehyderesins, furan resins, urea resins, imide resins, melamine resins, alkydresins, unsaturated polyester resins, aniline resins, sulfonamideresins, silicone resins, epoxy resins, their copolymer-based resins, aswell as by mixtures of at least two different kinds of resin from amongthe above-mentioned, and the thermoplastic resins exemplified byolefinic resins, such as polyethylene, low-density polyethylene,high-density polyethylene, ultra-high molecular weight polyethylene,polypropylene, and ethylene/propylene copolymers consisting ofhomopolymers and copolymers of alpha-olefins such as ethylene,propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, as well asethylene(meth)acrylate ester copolymers and ethylene/vinyl acetatecopolymers consisting of copolymers of the alpha-olefins with vinylacetate, methylmethacrylate, maleic acid and other monomers other thanalpha-olefins; acrylic resins, such as homopolymers or copolymers ofacrylic acid, methacrylic acid, methyl (meth)acrylate, butyl(meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylcyclohexyl(meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate,2-hydroxyethyl (meth)acrylate, glycidyl (meth)acrylate,diethylaminoethyl (meth)acrylate, and other (meth)acrylic acid esters,ethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate,neopentyl glycol di(meth)acrylate and other multifunctional(meth)acrylates and other acrylic monomers, as well as copolymers of theacrylic monomers with styrene, alpha-methylstyrene, and other styrenemonomers, vinyl acetate, vinyl chloride, vinylidene chloride, and othervinyl monomers, phenylmaleimide, cyclohexylmaleimide, anhydrousmaleimide, and other maleimide monomers; halogenated vinyl resins, suchas polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoride,polyvinylidene fluoride, etc.; styrene resins, such as polystyrene, highimpact strength polystyrene, acrylonitrile/butadiene/styrene copolymers(ABS resins), acrylonitrile/styrene copolymers, acrylonitrile/acrylicrubber/styrene copolymers, acrylonitrile/ethylenepropylene rubbercopolymers, etc.; polyester resins, such as polyethylene terephthalate,polyethylene naphthalate, polyethylene terephthalate/isophthalate,polybutylene terephthalate/isophthalate, etc.; polyamide resins, such asNylon 6, Nylon 66, Nylon 6/66, Nylon 6/12, Nylon 610, Nylon 612, Nylon11, Nylon 12, etc.; polyvinyl alcohol resins; polyacetal and otherpolyoxyalkylene resins; polycarbonate resins; polyvinyl acetate resins;polysulfone resins; polyether sulfone resins; polyphenylene sulfide andother polyarylene sulfide resins; polyarylate resins; polyimide resins;polyamideimide resins, polyether imide resins; polyether ether ketoneresins; liquid crystal polyester resins; polytetrafluoroethylene,ethylene/tetrafluoroethylene copolymers, and other fluorine resins;styrene elastomers, olefinic elastomers, urethane elastomers, fluorineelastomers, vinyl chloride elastomers, polyamide elastomers, polyesterelastomers, and other thermoplastic elastomer resins; and mixtures andcopolymers of two or more of the above thermoplastic resins.

When the silicone resin composition of the present invention is combinedwith organic resins, there are no limitations concerning the amountadded, however, preferably, the amount should be in the range of from0.1 to 100 parts by weight, and, especially preferably, in the range offrom 0.5 to 50 parts by weight per 100 parts by weight of the organicresin.

Another embodiment of the present invention is a curable resincomposition comprising:

-   -   (I) a curable resin,    -   (II) a silicone resin with a softening point exceeding 25° C.,        represented by the average unit formula        (R¹SiO_(3/2))_(a)(R² ₂SiO_(2/2))_(b)(R³        ₃SiO_(1/2))_(c)(SiO_(4/2))_(d)(XO_(1/2))_(e),        where R¹, R², and R³ stand for identical or different monovalent        hydrocarbon groups or epoxy-containing organic groups such that,        of the total number of R¹, R², and R³ groups in the molecule,        0.1 to 40 mol % comprises epoxy-containing organic groups and        not less than 10 mol % comprises phenyl groups, X is a hydrogen        atom or alkyl group, a is a positive number, b is 0 or a        positive number, c is 0 or a positive number, d is 0 or a        positive number, and e is 0 or a positive number such that b/a        is a number from 0 to 10, c/a is a number from 0 to 0.5,        d/(a+b+c+d) is a number from 0 to 0.3, and e/(a+b+c+d) is a        number from 0 to 0.4, and    -   (III) a silicone resin that is liquid at 25° C.

The curable resin of component (I) is the main ingredient of the presentembodiment and is not subject to any limitations so long as it iscurable. The methods used for curing it are exemplified by heat curing,curing with UV, ionizing radiation, and other high-energy beams,moisture curing, condensation type curing, and addition reaction curing.In addition, there are no limitations concerning its physical state,which means that the resin may be either in a liquid or in a solid stateat 25° C. Component (I) is exemplified by the above-described curableresins and more preferably, by epoxy resins, phenolic resins, imideresins, or silicone epoxy resins.

There are no particular limitations concerning the epoxy resins so longas they have glycidyl groups and alicyclic epoxy groups. Specifically,the resins are exemplified by o-cresol novolak type epoxy resins,phenolic novolak type epoxy resins, biphenyl type epoxy resins,biphenylaralkyl type epoxy resins, biphenyl novolak type epoxy resins,bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenolAD type epoxy resins, bisphenol-S type epoxy resins, dicyclopentadienetype epoxy resins, naphthalene type epoxy resins, anthracene type epoxyresins, naphthol aralkyl type epoxy resins, polyvinyl phenol type epoxyresins, diphenylmethane type epoxy resins, diphenylsulfone type epoxyresins, triphenol alkane type epoxy resins, cresol-naphtholco-condensation type epoxy resins, bisphenylethylene type epoxy resins,fluorene type epoxy resins, stilbene type epoxy resins, spyrocumaronetype epoxy resins, norbornene type epoxy resins, halogenated epoxyresins, imido-containing epoxy resins, maleimido-containing epoxyresins, allyl-modified epoxy resins, epoxy resins obtained from heavyoil and pitch, and, furthermore, in order to improve the waterrepellency of the resultant cured products and to reduce stress in thecured products, epoxy resins containing chemically bonded silane,polyalkylsiloxane, or fluoroalkyl groups. Especially preferable arecrystalline resins, exemplified by biphenyl type epoxy resins, bisphenolA type epoxy resins, bisphenol F type epoxy resins, stilbene type epoxyresins, biphenyl ether type epoxy resins, and biphenyl sulfone typeepoxy resins, and, more specifically, by biphenyl type epoxy resinsrepresented by the general formula:

by biphenyl type epoxy resins represented by the general formula:

by bisphenol A type epoxy resins represented by the general formula:

by bisphenol F type epoxy resins represented by the general formula:

by stilbene type epoxy resins represented by the general formula:

by biphenyl ether type epoxy resins represented by the general formula:

and by biphenyl sulfone type epoxy resins represented by the generalformula:

In the formulas, R stands for identical or different hydrogen atoms oralkyl groups, with the alkyl groups of R exemplified by methyl, ethyl,propyl, i-propyl, n-butyl, sec-butyl, and tert-butyl groups. Inaddition, subscript n in the formulas is a positive integer. Because ofthe excellent moldability of the composition and excellent flameretardant properties of the resultant cured products, biphenyl typeepoxy resins are preferable as the crystalline epoxy resins of component(I). The biphenyl type epoxy resins are exemplified by4,4′-bis(2,3-epoxypropoxy)biphenyl,4,4′-bis(2,3-epoxypropoxy)-3,3′,5,5′-tetramethylbiphenyl,4,4′-bis(2,3-epoxypropoxy)-3,3′,5,5′-tetraethylbiphenyl,4,4′-bis(2,3-epoxypropoxy)-3,3′,5,5′-tetraethylbiphenyl, and by4,4′-bis(2,3-epoxypropoxy)-3,3′,5,5′-tetrabutylbiphenyl, which can beobtained, for instance, by purchasing YX4000HK resins from Yuka ShellEpoxy Kabushiki Kaisha.

In addition, the phenolic resins are specifically exemplified bypolyvinylphenol type phenolic resins, phenol-novolak type phenolicresins, cresol-novolak type phenolic resins, biphenol type phenolicresins, biphenol aralkyl type phenolic resins, naphthol type phenolicresins, terpene type phenolic resins, phenoldicyclopentadiene typephenolic resins, phenol aralkyl type phenolic resins, naphthol aralkyltype phenolic resins, triphenol alkane type phenolic resins,dicyclopentadiene type phenolic resins, cresol-naphthol co-condensationtype phenolic resins, xylene-naphthol co-condensation type phenolicresins, phenolic resins obtained from heavy oil and pitch, and,furthermore, in order to improve the water repellency of the resultantcured products and to reduce stress in the cured products, phenolicresins containing chemically bonded silane, polyalkylsiloxane, orfluoroalkyl groups. There are no particular limitations concerning thetype of the phenolic resins. They are exemplified by the phenol aralkyltype, biphenol type, naphthol type, novolak type, and the like. Phenolaralkyl type phenolic resins are preferred because of the superior flameretardant properties of the cured products obtained by curing thecomposition. Such phenol aralkyl type phenolic resins are exemplified byphenol aralkyl type phenolic resins represented by the general formula:

by phenol aralkyl type phenolic resins represented by the generalformula:

by phenol aralkyl type phenolic resins represented by the generalformula:

and by phenol aralkyl type phenolic resins represented by the generalformula:

Subscript n in the formulas above is a positive integer. Such phenolaralkyl type phenolic resins can be obtained, for instance, bypurchasing the Milex XLC-3L line of products from Mitsui Chemicals, Inc.

It is also preferable to use curable resin compositions that arecombinations of epoxy resins and phenolic resins. From the standpoint ofmoldability, crystalline biphenyl type epoxy resins are preferable asthe epoxy resins, and, furthermore, their combinations with phenolaralkyl type phenolic resins are particularly preferable as far as thephenolic resins are concerned. In this case, there are no particularlimitations concerning the proportion, in which the epoxy resins andphenolic resins are combined, it is, however, preferable that the ratioof epoxy functional groups/phenol functional groups should be in therange of from 0.5 to 2.5. In addition, the epoxy resins and phenolicresins can be mixed in advance or added separately during mixing withcomponent (II) and component (III).

Component (II), which is a component used to improve the flame retardantproperties of the cured resin obtained by curing the curable resincomposition without decreasing the moldability of the presentcomposition, is a silicone resin with a softening point exceeding 25°C., represented by the average unit formula (R¹SiO_(3/2))_(a)(R²₂SiO_(2/2))_(b)(R³ ₃SiO_(1/2))_(c)(SiO_(4/2))_(d)(XO_(1/2))_(e). In theformula above, R¹, R², and R³ stand for identical or differentmonovalent hydrocarbon groups or epoxy-containing organic groupsexemplified by the same groups as those described above. Of the totalnumber of R¹, R², and R³ groups in the molecule, 0.1 to 40 mol %comprises epoxy-containing organic groups. This is due to the fact thatwhen the content of the epoxy-containing organic groups is below thelower end of the above-mentioned range, bleeding occurs during themolding of the resultant curable resin composition and the flexibility,moisture resistance, and thermal shock resistance of the resultant curedresin exhibit a tendency to decrease while, on the other hand, when thecontent exceeds the upper end of the above-mentioned range, themechanical characteristics of the resultant cured products tend todecrease. In addition, due to their having superior affinity forcomponent (I), providing good dispersibility, and imparting sufficientflame retardant properties to the resultant cured resin, not less than10 mol % of the total number of R¹, R², and R³ groups has to includephenyl groups. Preferably, phenyl groups should comprise not less than10 mol % of R¹, and even more preferably, phenyl groups should comprisenot less than 30 mol % of R¹. In addition, X in the formula above is ahydrogen atom or alkyl group, exemplified by the same groups as thosementioned above.

In the formula above, subscript a is a positive number, subscript b is 0or a positive number, subscript c is 0 or a positive number, subscript dis 0 or a positive number, and subscript e is 0 or a positive numbersuch that b/a is a number from 0 to 10, c/a is a number from 0 to 0.5,d/(a+b+c+d) is a number from 0 to 0.3, and e/(a+b+c+d) is a number from0 to 0.4. This is due to the fact that the softening point of a siliconeresin with a b/a exceeding 10 may drop conspicuously and its affinityfor component (I) may also decrease. In addition, a silicone resin witha c/(a+b+c) exceeding 0.3 has a tendency toward decreased dispersibilityin component (I).

There are no limitations concerning the weight-average molecular weightof component (II). Preferably, however, it should be in the range offrom 500 to 50,000, and more preferably, in the range of from 500 to10,000. In addition, although there are no particular limitations if thesoftening point of component (II) exceeds 25° C., preferably, it shouldbe in the range of from 40 to 250° C. and more preferably, in the rangeof from 40 to 150° C. This is due to the fact that silicone resin with asoftening point below the lower end of the above-mentioned range bleedsduring the molding of the curable resin composition, therebycontaminating the mold, and tends to decrease the mechanicalcharacteristics of the cured products obtained by curing theabove-mentioned composition. On the other hand, silicone resin with asoftening point exceeding the upper end of the above-mentioned rangeexhibits a tendency towards increased difficulty of uniform dispersionin component (I). There are no particular limitations concerning themethods used to regulate the characteristics of such component (II),which are exemplified by the same methods as those described above.

In the curable silicone resin composition, there are no limitationsconcerning the content of component (II), which, preferably, should bein the range of from 0.1 to 500 parts by weight and more preferably, inthe range of from 0.5 to 100 parts by weight per 100 parts by weight ofcomponent (I). This is due to the fact that if the content of component(II) is below the lower end of the above-mentioned range, it may not bepossible to obtain cured resin possessing superior flexibility, moistureresistance, and thermal shock resistance, and, on the other hand, if itexceeds the upper end of the above-mentioned range, the mechanicalstrength of the cured resin may dramatically decrease.

Component (III), a silicone resin liquid at 25° C., is a component usedto improve the moldability of the present composition without causingdeterioration in its flame retardant properties. Although there are noparticular limitations concerning the viscosity of component (III) at25° C., preferably, its viscosity should be in the range of from 5 to100,000 mPa·s and more preferably, in the range of from 10 to 5,000mPa·s. In addition, although there are no limitations concerning thenumber average molecular weight of component (III), preferably, asconverted to standard polystyrene, it should be in the range of from 500to 5,000 and more preferably in the range of from 1,000 to 4,000.

There are no particular limitations concerning the molecular structureof component (III), however, in the same manner as with component (II),this component is preferably a silicone resin having at least one unitselected from the group comprising units represented by the formulaR¹SiO_(3/2) (T-units), units represented by the formula R² ₂SiO_(2/2)(D-units), units represented by the formula R³ ₃SiO_(1/2) (M-units), andunits represented by the formula SiO_(4/2) (Q-units). In addition,component (III) may have silanol groups or silicon-bonded alkoxy groupsand other hydrolyzable groups. Such component (III) is represented, forinstance, by the average unit formula (R¹SiO_(3/2))_(a)(R²₂SiO_(2/2))_(b)(R³ ₃SiO_(1/2))_(c)(SiO_(4/2))_(d)(XO_(1/2))_(e). In theformula above, R¹, R², and R³ stand for identical or differentmonovalent hydrocarbon groups or epoxy-containing organic groups,exemplified by the same groups as those described above. In addition, inthe formula above, X is a hydrogen atom or alkyl group, exemplified bythe same groups as those described above. Also, in the formula above,subscript a is a positive number, subscript b is 0 or a positive number,subscript c is 0 or a positive number, subscript d is 0 or a positivenumber, and subscript e is 0 or a positive number such that b/a is anumber from 0 to 10, c/a is a number from 0 to 0.5, d/(a+b+c+d) is anumber from 0 to 0.3, and e/(a+b+c+d) is a number from 0 to 1. There areno limitations concerning the method of preparing component (III). Itcan be prepared by the same method as the one used for theabove-described component (II).

In the curable silicone resin composition, there are no limitationsconcerning the content of component (III), but it is preferable,however, that the content should be in the range of from 0.15 to 200parts by weight and more preferably, in the range of from 0.5 to 100parts by weight per 100 parts by weight of component (I). This is due tothe fact that if the content of component (III) is lower than the lowerend of the above-mentioned range, there is a possibility that it may beimpossible to obtain cured resin possessing superior flexibility,moisture resistance, and thermal shock resistance, and, on the otherhand, if it exceeds the upper end of the above-mentioned range, there isa possibility that the mechanical strength of the cured resin mayconspicuously decrease.

So long as the object of the present invention is not impaired, thecurable silicone resin composition may contain (IV) inorganic fillers asother optional components. Component (IV) is exemplified by glass fiber,asbestos, alumina fiber, ceramic fiber including alumina and silica asingredients, boron fiber, zirconia fiber, silicon carbonate fiber, metalfiber, and other fibrous fillers; glassy silica, crystalline silica,precipitated silica, fumed silica, calcined silica, zinc oxide, calcinedclay, carbon black, glass beads, alumina, talc, calcium carbonate, clay,aluminum hydroxide, magnesium hydroxide, barium sulfate, titaniumdioxide, aluminum nitride, boron nitride, silicon carbonate, aluminumoxide, magnesium oxide, titanium oxide, beryllium oxide, kaolin, mica,zircona, and other pulverulent fillers, as well as mixture of two ormore of the above fillers. In addition, there are no limitationsconcerning the average particle size and shape of component (IV), but itis preferable to use spherical silica with an average particle size of0.1 to 40 μm.

In the composition of the present invention, there are not limitationsconcerning the content of component (IV), however, the content ispreferably 400 to 1,200 parts by weight per 100 parts by weight of thetotal of from component (I) through component (III). This is due to thefact that there may be an increase in the thermal expansion coefficientof the resultant cured resin, cracks may appear as a result of stress,and flame retardant properties may deteriorate if the content ofcomponent (IV) is less then the lower end of the above-mentioned range,and, on the other hand, the moldability of the resultant composition maydecrease if it exceeds the upper end of the above-mentioned range.

In the curable silicone resin composition, silane coupling agents,titanate coupling agents, and other coupling agents can be used to forman excellent dispersion of component (IV) in component (I) and improvethe affinity between component (I) and component (IV). The silanecoupling agents are exemplified 3-glycidoxypropyltrimethoxysilane,3-glycidoxypropylmethyldiethoxysilane,2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and other epoxy-containingalkoxysilanes; N-(2-aminoethyl)-3-aminopropyltrimethoxysilane,3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane,and other amino-containing alkoxysilanes;3-mercaptopropyltrimethoxysilane, and other mercapto-containingalkoxysilanes. In addition, the titanate coupling agents are exemplifiedby i-propoxy titanium tri(i-isostearate).

In addition, the curable silicone resin composition preferably containscure promoters used to promote the curing reaction of component (I).Triphenylphosphine, tributylphosphine, trip-methylphenyl)phosphine,tri(nonylphenyl)phosphine, triphenylphosphine-triphenyl borate,tetraphenylphosphine-tetraphenyl borate, and other phosphorus compounds;triethylamine, benzyldimethylamine, alpha-methylbenzyldimethylamine,1,8-diazabicyclo[5.4.0]undecene-7, and other tertiary amine compounds;2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole andother imidazole compounds can be suggested as examples of the curepromoters.

If necessary, the curable silicone resin composition may also containthermoplastic resins, thermoplastic elastomers, organosynthetic rubber,silicones, and other stress-reducing agents; carnauba wax, higheraliphatic acids, synthetic waxes, and other waxes; carbon black andother colorants; halogen trapping agents, etc.

There are no limitations concerning the methods used to adjust thecurable silicone resin composition; thus, it can be prepared byuniformly mixing from component (I) through component (III) and otheroptional components. The dispersibility of component (II) can beimproved if component (I) is mixed with a silicone resin compositionprepared by mixing component (III) with component (II) and advance. Inaddition, in case component (IV) is added as an optional component, themethod of preparation may be exemplified by a process, in which, aftermixing component (IV) with component (I), component (II), component(III), and other optional components are uniformly mixed therewith, and,at such time, integral blend processes be used by adding coupling agentsto component (I) and component (IV), or processes, in which, afterpre-treating the surface of component (IV) with a coupling agent, it ismixed with component (I). In addition, the equipment used to prepare thecurable silicone resin composition is exemplified by single- ordouble-spindle continuous mixers, two roll mills, Ross mixers, andkneader-mixers.

Because the curable resin composition of the present invention hassuperior flowability prior to curing and the cured resin obtained aftercuring possesses superior flame retardant properties, it can be used forpreparing electrical or electronic element sealing resin compositions,paint, coating agents, adhesives, etc. using transfer molding, injectionmolding, potting, casting, powder coating, and other techniques. Thecurable resin composition of the present invention is particularlysuitable for semiconductor sealing applications using transfer pressing.

EXAMPLES

The following examples are disclosed to further teach, but not limit,the silicone resin composition, curable resin composition, and curedresin of the present invention, which is properly delineated by theappended claims. As used herein, “Me” stands for “methyl,” “Ph” standsfor “phenyl,” “Ep” stands for “3-glycidoxypropyl,” and “Pr” stands for“isopropyl.” In addition, the word “viscosity” refers to values obtainedat 25° C.

The characteristics of the curable resin composition and the cured resinproduced therefrom were measured by the methods described below. Inaddition, the curable resin composition was transfer press molded at175° C. for 2 minutes under 70 kgf/cm² and then cured by post-curing at180° C. for 5 hours.

Moldability

-   -   Spiral flow: measured at 175° C. and 70 kgf/cm² by the method        prescribed by an EMMI standard.    -   Mold contamination: after molding 5 disks with a diameter of 50        mm and a thickness of 2 mm in a row, the tarnishing of the        chrome-plated surface of the mold was observed visually,        designating cases, in which there was no mold contamination as        ◯, cases, in which there was a thin tarnishing layer on the        surface of the mold, as Δ, and cases, in which there was        contamination on the surface of the mold, as x.    -   Burrs: the length of the burrs formed during molding in a burr        measurement mold (20 μm-deep grooves), designating cases, in        which the length of the burrs was not more than 2 mm, as ◯,        cases, in which burrs exceeded 2 mm but were not larger than 10        mm, as Δ, and cases, in which the burrs exceeded 10 mm, as x.

Flame Retardant Properties:

-   -   LOI value: the lowest oxygen concentration required for burning        was determined using an oxygen index test apparatus and test        specimens with a thickness of {fraction (1/16)} inch (about        1.6 mm) in accordance with JIS K 7201 “Test Method For        Determination of Burning Behavior Of Plastics By Oxygen Index.”        An average value of the lowest oxygen concentration was obtained        from 5 test specimens.    -   Burning time: test specimens with a thickness of {fraction        (1/16)} inch (about 1.6 mm) were prepared and their burning        times (in seconds) were measured in accordance with Standard        UL94 (Standard for test for flammability of plastic material for        parts in devices and appliances) established by Underwriters        Laboratories, Inc.

The characteristics of the silicone resin and silicone resin compositionwere measured in the following manner.

-   -   Softening point: using a melting point determination apparatus        (the “Micro-Melting Point Apparatus from Kabushiki Kaisha        Yanagimoto Seisakusho), the silicone resin was melted by raising        the temperature at a rate of 1° C./min, with the temperature at        which the resin turned to drops used as the softening point.    -   Melt viscosity: using a Model DV-III Programmable Rheometer from        Brookfield Engineering Laboratories Inc., the silicone resin was        heated, raising it temperature from room temperature at a        temperature rise rate of 2° C./min and maintaining it for 20 min        at 100° C. and 160° C. The melt viscosities at the corresponding        temperatures were measured.    -   Viscosity: viscosity was measured using a rotational viscometer        (the Vismetron VG-DA from Shibaura System, rotor: No. 4, speed:        60 rpm).

Reference Example 1

250 g water and 400 g toluene were placed in a 2000-mL flask equippedwith a thermometer and a reflux condenser, and a mixture of 300 gphenyltrichlorosilane and 200 g toluene was added thereto in a dropwisemanner while cooling the flask in an ice bath. Upon termination of thedropwise addition, the mixture was refluxed for 6 hours with heating,after which the toluene solution was separated. The toluene solution wasrepeatedly washed with water such until the wash liquid became neutral.After that, toluene was eluted by heating the toluene solution underreduced pressure, yielding 177.7 g of a white solid.

116.0 g of the above-mentioned white solid, 20.2 g3-glycidoxypropylmethyldimethoxysilane, 19.1 g dimethyldimethoxysilane,150 g toluene, and 0.15 g cerium hydroxide were placed in a 500-mL flaskequipped with a thermometer and a Dean-Stark tube. Next, 10.0 g waterwas added to the system, whereupon, under heating, the produced methanoland water were eluted. When the elution of the water ceased, the systemwas cooled down, and another 10.0 g water added to the system. Afterthat, by heating the system, the produced methanol and water wereeluted, and the solution was refluxed for 6 hours with heating. Aftercooling it down, a neutralization treatment was carried out by adding0.08 g acetic acid to the system. Next, the system was washed with water3 times. The resultant toluene solution was placed in a 500-mL flaskequipped with a Dean-Stark tube and subjected to azeotropic dehydration.Impurities were filtered off and 140 g of a colorless transparent solidwas obtained by eluting toluene by heating the filtrate under reducedpressure. It was confirmed that the colorless transparent solid was a3-glycidoxypropyl-containing silicone resin having a weight-averagemolecular weight of 2600, a softening point of 73° C., a melt viscosityof 540,000 mPa·s at 100° C., a melt viscosity of 70,000 mPa·s at 160°C., and an epoxy equivalent of 1620, represented, according to²⁹Si-nuclear magnetic resonance spectral analysis, by the average unitformula:(PhSiO_(3/2))_(0.78)(Me₂SiO_(2/2))_(0.14)(EpMeSiO_(2/2))_(0.08)Relative to all silicon-bonded organic groups, the content of3-glycidoxypropyl groups in the silicone resin was 7 mol %, and thecontent of phenyl groups was 64 mol %.

Reference Example 2

180 g toluene, 60 g isopropyl alcohol, and 250 g water were placed in a2000-mL four-neck flask fitted with a stirrer, cooler, dropping funnel,and a temperature gauge and a mixed solution of 147 gphenyltrichlorosilane and 52.8 g isopropyltrichlorosilane was addedthereto in a dropwise manner while cooling the flask in an ice bath.Upon termination of the dropwise addition, the mixture was stirred for30 minutes at room temperature, after which it was refluxed with heatingfor 3 hours in order to bring hydrolysis to completion. Next, theresultant toluene solution was allowed to stand and the water layer wasremoved, whereupon it was repeatedly washed with water such until thewash liquid became neutral. After that, the toluene solution wassubjected to azeotropic dehydration. After cooling, insoluble matter wasremoved by filtration, and 115.2 g of a colorless transparent solid wasobtained by eluting the toluene by heating the filtrate under reducedpressure. It was confirmed that the colorless transparent solid was asilicone resin having a weight-average molecular weight of 1600, asoftening point of 80° C., a melt viscosity of 200,000 mPa·s at 100° C.,a melt viscosity of 3,000 mPa·s at 160° C., represented, according to²⁹Si-nuclear magnetic resonance spectral analysis, by the average unitformula:(PhSiO_(3/2))_(0.70)(PrSiO_(3/2))_(0.30)(HO_(1/2))_(0.43).

Reference Example 3

A liquid silicone resin with a number-average molecular weight of 1200and a viscosity of 120 mPa·s, represented by the average unit formula:(PhSiO_(3/2))_(0.67)(Me₂SiO_(2/2))_(0.33)(MeO_(1/2))_(0.74)was prepared by subjecting phenyltrimethoxysilane anddimethyldimethoxysilane to a reaction of co-hydrolysis and condensation.

Reference Example 4

A liquid silicone resin with a number-average molecular weight of 2000and a viscosity of 1300 mPa·s, represented by the average unit formula:(PhSiO_(3/2))_(0.62)(Me₂SiO_(2/2))_(0.30)(EpMeSiO_(2/2))_(0.08)(MeO_(1/2))_(0.75)was prepared by subjecting phenyltrimethoxysilane,dimethyldimethoxysilane, and methyl(3-glycidoxypropyl)dimethoxysilane toa reaction of co-hydrolysis and condensation.

Application Example 1

After mixing 16.2 parts by weight of the silicone resin prepared inReference Example 1 with 1.8 parts by weight of the silicone resinprepared in Reference Example 3 in a 30-mL kneader (Brabender mixer fromToyo Seiki Co., Ltd.) for 5 minutes at 120° C., a transparent uniformsilicone resin composition was prepared by cooling the mixture to roomtemperature. The melt viscosity of the silicone resin composition wasmeasured. The results are listed in Table 1.

Application Example 2

16.2 parts by weight of the silicone resin prepared in Reference Example1 was placed in a four-neck flask and dissolved at room temperature byadding 50 mL toluene. 1.8 parts by weight of the silicone resin preparedin Reference Example 4 was added to and dissolved in this solution,whereupon toluene was eluted under 10 mmHg at 100° C., preparing atransparent silicone resin composition. The melt viscosity of thesilicone resin composition was measured. The results are listed in Table1.

Comparative Example 1

In the same manner as in Application Example 1, 16.2 parts by weight ofthe silicone resin prepared in Reference Example 2 and 1.8 parts byweight of the silicone resin prepared in Reference Example 3 were mixedand then cooled to prepare a white opaque silicone resin composition.The melt viscosity of the silicone resin composition was measured. Theresults are listed in Table 1. TABLE 1 Example Type ComparativeApplication Examples Example Parameter 1 2 1 Melt Viscosity (mPa · s)100° C. 24,000 30,000 400,000 160° C.  1,000  1,000  4,000 ExternalAppearance Transparent, Transparent, White, non- uniform uniform uniform

Practical Example 1

27 g of aromatic polycarbonate resin (Taflon A1900 from IdemitsuPetrochemical Co., Ltd.) and 3 g of the silicone resin compositionprepared in Application Example 1 were mixed for 5 minutes at 280° C. ina 30-mL kneader (Brabender mixer from Toyo Seiki Co., Ltd.), after whichtest specimens were fabricated in an injection molding machine. Theoxygen index (LOI) of the specimens was measured in accordance with JISK 7201 “Test Method For Determination of Burning Behavior Of Plastics ByOxygen Index.” The results are listed in Table 2.

Practical Example 2

27 g of aromatic polycarbonate resin (Taflon A1900 from IdemitsuPetrochemical Co., Ltd.) and 3 g of the silicone resin compositionprepared in Application Example 2 were mixed for 5 minutes at 280° C. ina 30-mL kneader (Brabender mixer from Toyo Seiki Co., Ltd.), after whichtest specimens were fabricated in an injection molding machine. Theoxygen index (LOI) of the specimens was measured in the same manner asin Practical Example 1. The results are listed in Table 2.

Practical Example 3

27 g of aromatic polycarbonate resin (Taflon A1900 from IdemitsuPetrochemical Co., Ltd.) and 3 g of the silicone resin compositionprepared in Comparative Example 1 were mixed for 5 minutes at 280° C. ina 30-mL kneader (Brabender mixer from Toyo Seiki Co., Ltd.), after whichtest specimens were fabricated in an injection molding machine. Theoxygen index (LOI) of the specimens was measured in the same manner asin Practical Example 1. The results are listed in Table 2. TABLE 2Example Type Practical Examples Parameter 1 2 3 LOI 35 35 28

Application Example 3

A curable epoxy resin composition was prepared by uniformly melt-mixing46.9 parts by weight of crystalline biphenyl type epoxy resin (EpicoatYX4000H from Yuka Shell Epoxy Kabushild Kaisha; epoxy equivalent=190,melting point=105° C.), 43.1 parts by weight of phenol aralkyl typephenolic resin (Milex XLC-3L from Mitsui Chemicals, Inc.; phenolichydroxyl equivalent=168) (amount at which the mole ratio of the phenolichydroxyl groups of this phenolic resin relative to the epoxy groups ofthe above-mentioned epoxy resin is 1.0), 18 parts by weight of thesilicone resin composition prepared in Application Example 1, 510 partsby weight of amorphous spherical silica with an average particle size of14 μm (FB-48× from Denki Kagaku Kogyo Kabushiki Kaisha), 0.4 parts byweight of carbon black, 1 part by weight3-glycidoxypropyltrimethoxysilane, 0.9 parts by weight of carnauba wax,and 0.66 parts by weight of triphenylphosphine in a two roll mill withheating. The characteristics of the curable epoxy resin composition andcured resin made therefrom were measured. The results are listed inTable 3.

Application Example 4

A curable epoxy resin composition was prepared by uniformly melt-mixing46.9 parts by weight of crystalline biphenyl type epoxy resin (EpicoatYX4000H from Yuka Shell Epoxy Kabushiki Kaisha; epoxy equivalent=190,melting point=105° C.), 43.1 parts by weight of phenol aralkyl typephenolic resin (Milex XLC-3L from Mitsui Chemicals, Inc.; phenolichydroxyl equivalent=168) (amount at which the mole ratio of the phenolichydroxyl groups of this phenolic resin relative to the epoxy groups ofthe above-mentioned epoxy resin is 1.0), 18 parts by weight of thesilicone resin composition prepared in Application Example 2, 510 partsby weight of amorphous spherical silica with an average particle size of14 μm (FB-48× from Denki Kagaku Kogyo Kabushild Kaisha), 0.4 parts byweight of carbon black, 1 part by weight3-glycidoxypropyltrimethoxysilane, 0.9 parts by weight of carnauba wax,and 0.66 parts by weight of triphenylphosphine in a two roll mill withheating. The characteristics of the curable epoxy resin composition andcured resin made therefrom were measured. The results are listed inTable 3.

Comparative Example 2

A curable epoxy resin composition was prepared by uniformly melt-mixing46.9 parts by weight of crystalline biphenyl type epoxy resin (EpicoatYX4000H from Yuka Shell Epoxy Kabushiki Kaisha; epoxy equivalent=190,melting point=105° C.), 43.1 parts by weight of phenol aralkyl typephenolic resin (Milex XLC-3L from Mitsui Chemicals, Inc.; phenolichydroxyl equivalent=168) (amount at which the mole ratio of the phenolichydroxyl groups of this phenolic resin relative to the epoxy groups ofthe above-mentioned epoxy resin is 1.0), 18 parts by weight of thesilicone resin prepared in Reference Example 1, 510 parts by weight ofamorphous spherical silica with an average particle size of 14 μm(FB-48× from Denki Kagaku Kogyo Kabushiki Kaisha), 0.4 parts by weightof carbon black, 1 part by weight 3-glycidoxypropyltrimethoxysilane, 0.9parts by weight of carnauba wax, and 0.66 parts by weight oftriphenylphosphine in a two roll mill with heating. The characteristicsof the curable epoxy resin composition and cured resin made therefromwere measured. The results are listed in Table 3.

Comparative Example 3

A curable epoxy resin composition was prepared by uniformly melt-mixing46.9 parts by weight of crystalline biphenyl type epoxy resin (EpicoatYX4000H from Yuka Shell Epoxy Kabushiki Kaisha; epoxy equivalent=190,melting point=105° C.), 43.1 parts by weight of phenol aralkyl typephenolic resin (Milex XLC-3L from Mitsui Chemicals, Inc.; phenolichydroxyl equivalent=168) (amount at which the mole ratio of the phenolichydroxyl groups of this phenolic resin relative to the epoxy groups ofthe above-mentioned epoxy resin is 1.0), 18 parts by weight of thesilicone resin composition prepared in Comparative Example 1, 510 partsby weight of amorphous spherical silica with an average particle size of14 μm (FB-48× from Denki Kagaku Kogyo Kabushiki Kaisha), 0.4 parts byweight of carbon black, 1 part by weight3-glycidoxypropyltrimethoxysilane, 0.9 parts by weight of carnauba wax,and 0.66 parts by weight of triphenylphosphine in a two roll mill withheating. The characteristics of the curable epoxy resin composition andcured resin made therefrom were measured. The results are listed inTable 3.

Comparative Example 4

A curable epoxy resin composition was prepared by uniformly melt-mixing46.9 parts by weight of crystalline biphenyl type epoxy resin (EpicoatYX4000H from Yuka Shell Epoxy Kabushild Kaisha; epoxy equivalent=190,melting point=105° C.), 43.1 parts by weight of phenol aralkyl typephenolic resin (Milex XLC-3L from Mitsui Chemicals, Inc.; phenolichydroxyl equivalent=168) (amount at which the mole ratio of the phenolichydroxyl groups of this phenolic resin relative to the epoxy groups ofthe above-mentioned epoxy resin is 1.0), 510 parts by weight ofamorphous spherical silica with an average particle size of 14 μm(FB-48X from Denki Kagaku Kogyo Kabushiki Kaisha), 0.4 parts by weightof carbon black, 1 part by weight 3-glycidoxypropyltrimethoxysilane, 0.9parts by weight of carnauba wax, and 0.66 parts by weight oftriphenylphosphine in a two roll mill with heating. The characteristicsof the curable epoxy resin composition and cured resin made therefromwere measured. The results are listed in Table 3.

Comparative Example 5

A curable epoxy resin composition was prepared by uniformly melt-mixing46.9 parts by weight of crystalline biphenyl type epoxy resin (EpicoatYX4000H from Yuka Shell Epoxy Kabushild Kaisha; epoxy equivalent=190,melting point=105° C.), 43.1 parts by weight of phenol aralkyl typephenolic resin (Milex XLC-3L from Mitsui Chemicals, Inc.; phenolichydroxyl equivalent=168) (amount at which the mole ratio of the phenolichydroxyl groups of this phenolic resin relative to the epoxy groups ofthe above-mentioned epoxy resin is 1.0), 18 parts by weight of thesilicone resin prepared in Reference Example 3, 510 parts by weight ofamorphous spherical silica with an average particle size of 14 μm(FB-48X from Denki Kagaku Kogyo Kabushiki Kaisha), 0.4 parts by weightof carbon black, 1 part by weight 3-glycidoxypropyltrimethoxysilane, 0.9parts by weight of carnauba wax, and 0.66 parts by weight oftriphenylphosphine in a two roll mill with heating. The characteristicsof the curable epoxy resin composition and cured resin made therefromwere measured. The results are listed in Table 3. TABLE 3 Example TypeApplication Examples Comparative Examples Parameter 3 4 2 3 4 5Moldability Spiral flow 33 33 26 45 29 48 (inch) Mold ◯ ◯ ◯ X ◯ Xcontamination Burrs ◯ ◯ ◯ X ◯ X Flame LOI 44 45 44 45 39 36 retardantBurning time 13 13 13 25 31 ≧40  properties (sec)

Application Example 5

A curable epoxy resin composition was prepared by uniformly melt-mixing46.9 parts by weight of crystalline biphenyl type epoxy resin (EpicoatYX4000H from Yuka Shell Epoxy Kabushiki Kaisha; epoxy equivalent=190,melting point=105° C.), 43.1 parts by weight of phenol aralkyl typephenolic resin (Milex XLC-3L from Mitsui Chemicals, Inc.; phenolichydroxyl equivalent=168) (amount at which the mole ratio of the phenolichydroxyl groups of this phenolic resin relative to the epoxy groups ofthe above-mentioned epoxy resin is 1.0), 18 parts by weight of thesilicone resin composition prepared in Application Example 1, 350 partsby weight of crushed amorphous silica with an average particle size of50 μm (from Tatsumori Co., Ltd.), 0.4 parts by weight of carbon black, 1part by weight 3-glycidoxypropyltrimethoxysilane, 0.9 parts by weight ofcarnauba wax, and 0.66 parts by weight of triphenylphosphine in a tworoll mill with heating. The following characteristics of the curableepoxy resin composition and cured resin made therefrom were measured.The results are listed in Table 4.

Dispersion Particle Size of Silicone Resin: Samples fabricated bymolding disks with a diameter of 10 cm and a thickness of 5 mm under apressure of 70 kgf/cm² at 175° C. for 3 minutes and post-curing them for5 hours at 180° C. were cut up into pieces and cut surfaces wereexamined with an electron microscope.

Water Absorption Coefficient: The same disks as the ones described abovewere placed in a pressure cooker vessel and kept at 120° C. for 10hours. After that, the coefficient was calculated from the weight changeratio obtained immediately after cooling and removing them from thevessel.

Mold Contamination: After molding 5 disks identical to the onesdescribed above in a row, the tarnishing of the chrome-plated surface ofthe mold was examined visually, designating cases, in which there was nomold contamination as ◯, cases, in which there was a thin tarnishinglayer on the surface of the mold, as Δ, and cases, in which there wascontamination on the surface of the mold, as x.

Application Example 6

A curable epoxy resin composition was prepared by uniformly melt-mixing46.9 parts by weight of crystalline biphenyl type epoxy resin (EpicoatYX4000H from Yuka Shell Epoxy Kabushiki Kaisha; epoxy equivalent=190,melting point=105° C.), 43.1 parts by weight of phenol aralkyl typephenolic resin (Milex XLC-3L from Mitsui Chemicals, Inc.; phenolichydroxyl equivalent=168) (amount at which the mole ratio of the phenolichydroxyl groups of this phenolic resin relative to the epoxy groups ofthe above-mentioned epoxy resin is 1.0), 18 parts by weight of thesilicone resin composition prepared in Application Example 2, 350 partsby weight of crushed amorphous silica with an average particle size of50 μm (from Tatsumori Co., Ltd.), 0.4 parts by weight of carbon black, 1part by weight 3-glycidoxypropyltrimethoxysilane, 0.9 parts by weight ofcarnauba wax, and 0.66 parts by weight of triphenylphosphine in a tworoll mill with heating. The characteristics of the curable epoxy resincomposition and cured resin made therefrom were measured in the samemanner as in Application Example 5. The results are listed in Table 4.

Comparative Example 6

A curable epoxy resin composition was prepared by uniformly melt-mixing46.9 parts by weight of crystalline biphenyl type epoxy resin (EpicoatYX4000H from Yuka Shell Epoxy Kabushiki Kaisha; epoxy equivalent=190,melting point=105° C.), 43.1 parts by weight of phenol aralkyl typephenolic resin (Milex XLC-3L from Mitsui Chemicals, Inc.; phenolichydroxyl equivalent=168) (amount at which the mole ratio of the phenolichydroxyl groups of this phenolic resin relative to the epoxy groups ofthe above-mentioned epoxy resin is 1.0), 18 parts by weight of thesilicone resin composition prepared in Comparative Example 1, 350 partsby weight of crushed amorphous silica with an average particle size of50 μm (from Tatsumori Co., Ltd.), 0.4 parts by weight of carbon black, 1part by weight glycidoxypropyltrimethoxysilane, 0.9 parts by weight ofcamauba wax, and 0.66 parts by weight of triphenylphosphine in a tworoll mill with heating. The characteristics of the curable epoxy resincomposition and cured resin made therefrom were measured in the samemanner as in Application Example 5. The results are listed in Table 4.

Comparative Example 7

A curable epoxy resin composition was prepared by uniformly melt-mixing46.9 parts by weight of crystalline biphenyl type epoxy resin (EpicoatYX4000H from Yuka Shell Epoxy Kabushiki Kaisha; epoxy equivalent=190,melting point=105° C.), 43.1 parts by weight of phenol aralkyl typephenolic resin (Milex XLC-3L from Mitsui Chemicals, Inc.; phenolichydroxyl equivalent=168) (amount at which the mole ratio of the phenolichydroxyl groups of this phenolic resin relative to the epoxy groups ofthe above-mentioned epoxy resin is 1.0), 18 parts by weight of thesilicone resin prepared in Reference Example 1, 350 parts by weight ofcrushed amorphous silica with an average particle size of 50 μm (fromTatsumori Co., Ltd.), 0.4 parts by weight of carbon black, 1 part byweight glycidoxypropyltrimethoxysilane, 0.9 parts by weight of carnaubawax, and 0.66 parts by weight of triphenylphosphine in a two roll millwith heating. The characteristics of the curable epoxy resin compositionand cured resin made therefrom were measured in the same manner as inApplication Example 5. The results are listed in Table 4. TABLE 4Example Type Application Comparative Examples Examples Parameter 5 6 6 7Dispersion particle size of silicone ≦5 ≦5 10˜20 10˜50 resin (μm)Coefficient of moisture absorption 0.4 0.5 0.8 0.9 (weight %) Moldcontamination ◯ ◯ X X

The silicone resin composition of the present invention has a low meltviscosity and excellent reactivity and dispersibility in organic resins.The curable resin composition of the present invention possessesexcellent moldability, forms cured resin of superior flame retardantproperties, and does not have an adverse impact on the human body andthe environment because it does not contain halogenated epoxy resins andantimony oxides. In addition, the cured resin of the present inventionhas little adverse impact on the human body and the environment andpossesses superior flame retardant properties.

1. A silicone resin composition comprising: (A) a silicone resin with asoftening point exceeding 25° C., represented by the average unitformula (R¹SiO_(3/2))_(a)(R² ₂SiO_(2/2))_(b)(R³₃SiO_(1/2))_(c)(SiO_(4/2))_(d)(XO_(1/2))_(e), wherein R¹, R², and R³ areindependently selected from the group consisting of monovalenthydrocarbon groups and epoxy-containing organic groups such that, of thetotal number of R¹, R², and R³ groups in the molecule, 0.1 to 40 mol %comprises epoxy-containing organic groups and not less than 10 mol %comprises phenyl groups, X is selected from the group consisting ofhydrogen atom and alkyl group, a is a positive number, b is 0 or apositive number, c is 0 or a positive number, d is 0 or a positivenumber, and e is 0 or a positive number such that b/a is a number from 0to 10, c/a is a number from 0 to 0.5, d/(a+b+c+d) is a number from 0 to0.3, and e/(a+b+c+d) is a number from 0 to 0.4, and (B) a silicone resinthat is liquid at 25° C.
 2. The silicone resin composition set forth inclaim 1, wherein not less than 10 mol % of R¹ in component (A) comprisesphenyl groups.
 3. The silicone resin composition set forth in claim 1,wherein the viscosity of component (B) at 25° C. is 5 to 100,000 mPa·s.4. The silicone resin composition set forth in of claims 1 whereincomponent (B) is a silicone resin represented by average unit formula(R¹SiO_(3/2))_(a)(R² ₂SiO_(2/2))_(b)(R³₃SiO_(1/2))_(c)(SiO_(4/2))_(d)(XO_(1/2))_(e), where R¹, R², and R³ standfor identical or different monovalent hydrocarbon groups orepoxy-containing organic groups, X is a hydrogen atom or alkyl group, ais a positive number, b is 0 or a positive number, c is 0 or a positivenumber, d is 0 or a positive number, and e is 0 or a positive numbersuch that b/a is a number from 0 to 10, c/a is a number from 0 to 0.5,d/(a+b+c+d) is a number from 0 to 0.3, and e/(a+b+c+d) is a number from0 to
 1. 5. The silicone resin composition set forth in claim 1, whereinthe amount of component (B) is 0.15 to 200 parts by weight per 100 partsby weight of component (A).
 6. A curable resin composition comprising:(I) a curable resin, (II) a silicone resin with a softening pointexceeding 25° C., represented by the average unit formula(R¹SiO_(3/2))_(a)(R² ₂SiO_(2/2))_(b)(R³₃SiO_(1/2))_(c)(SiO_(4/2))_(d)(XO_(1/2))_(e), where R¹, R², and R³ areindependently selected from the group consisting of monovalenthydrocarbon groups and epoxy-containing organic groups such that, of thetotal number of R¹, R², and R³ groups in the molecule, 0.1 to 40 mol %comprises epoxy-containing organic groups and not less than 10 mol %comprises phenyl groups, X is selected from the group consisting of ahydrogen atom and alkyl group, a is a positive number, b is 0 or apositive number, c is 0 or a positive number, d is 0 or a positivenumber, and e is 0 or a positive number such that b/a is a number from 0to 10, c/a is a number from 0 to 0.5, d/(a+b+c+d) is a number from 0 to0.3, and e/(a+b+c+d) is a number from 0 to 0.4, and (III) a siliconeresin that is liquid at 25° C.
 7. The curable resin composition setforth in claim 6, wherein component (I) is an epoxy resin.
 8. Thecurable resin composition set forth in claim 6, wherein component (I) isa crystalline epoxy resin.
 9. The curable resin composition set forth inclaim 6, wherein component (I) is a mixture of epoxy resin and phenolicresin.
 10. The curable resin composition set forth in claim 6, whereincomponent (I) is a mixture of a biphenyl type epoxy resin and a phenolaralkyl type epoxy resin.
 11. The curable resin composition set forth inclaim 6, wherein not less than 10 mol % of R¹ in component (II)comprises phenyl groups.
 12. The curable resin composition set forth inclaim 6, wherein the viscosity of component (III) at 25° C. is 5 to100,000 mPa·s.
 13. The curable resin composition set forth in claim 6,wherein component (III) is a silicone resin represented by average unitformula (R¹SiO_(3/2))_(a)(R² ₂SiO_(2/2))_(b)(R³₃SiO_(1/2))_(c)(SiO_(4/2))_(d)(XO_(1/2))_(e), where R¹, R², and R³ standfor identical or different monovalent hydrocarbon groups orepoxy-containing organic groups, X is a hydrogen atom or alkyl group, ais a positive number, b is 0 or a positive number, c is 0 or a positivenumber, d is 0 or a positive number, and e is 0 or a positive numbersuch that b/a is a number from 0 to 10, c/a is a number from 0 to 0.5,d/(a+b+c+d) is a number from 0 to 0.3, and e/(a+b+c+d) is a number from0 to
 1. 14. The curable resin composition set forth in claim 6, whereinthe amount of component (II) is 0.1 to 500 parts by weight and that ofcomponent (III) is 0.15 to 200 parts by weight per 100 parts by weightof component (I).
 15. A cured resin obtained by curing the curable resincomposition according to claim
 6. 16. The silicone resin composition setforth in claim 2 wherein the viscosity of component (B) at 25° C. is 5to 100,000 mPa·s.
 17. The silicone resin composition set forth in claim2 wherein component (B) is a silicone resin represented by average unitformula (R¹SiO_(3/2))_(a)(R² ₂SiO_(2/2))_(b)(R³₃SiO_(1/2))_(c)(SiO_(4/2))_(d)(XO_(1/2))_(e), where R¹, R², and R³ standfor identical or different monovalent hydrocarbon groups orepoxy-containing organic groups, X is a hydrogen atom or alkyl group, ais a positive number, b is 0 or a positive number, c is 0 or a positivenumber, d is 0 or a positive number, and e is 0 or a positive numbersuch that b/a is a number from 0 to 10, c/a is a number from 0 to 0.5,d/(a+b+c+d) is a number from 0 to 0.3, and e/(a+b+c+d) is a number from0 to
 1. 18. The silicone resin composition set forth in claim 3, whereincomponent (B) is a silicone resin represented by average unit formula(R¹SiO_(3/2))_(a)(R² ₂SiO_(2/2))_(b)(R³₃SiO_(1/2))_(c)(SiO_(4/2))_(d)(XO_(1/2))_(e), where R¹, R², and R³ standfor identical or different monovalent hydrocarbon groups orepoxy-containing organic groups, X is a hydrogen atom or alkyl group, ais a positive number, b is 0 or a positive number, c is 0 or a positivenumber, d is 0 or a positive number, and e is 0 or a positive numbersuch that b/a is a number from 0 to 10, c/a is a number from 0 to 0.5,d/(a+b+c+d) is a number from 0 to 0.3, and e/(a+b+c+d) is a number from0 to
 1. 19. The silicone resin composition set forth in claim 2, whereinthe amount of component (B) is 0.15 to 200 parts by weight per 100 partsby weight of component (A).
 20. The silicone resin composition set forthin claim 3, wherein the amount of component (B) is 0.15 to 200 parts byweight per 100 parts by weight of component (A).
 21. The silicone resincomposition set forth in claim 4, wherein the amount of component (B) is0.15 to 200 parts by weight per 100 parts by weight of component (A).22. The curable resin composition set forth in claim 7, whereincomponent (I) is a crystalline epoxy resin.
 23. The curable resincomposition set forth in claim 7, wherein component (I) is a mixture ofepoxy resin and phenolic resin.
 24. The curable resin composition setforth in claim 8, wherein component (I) is a mixture of epoxy resin andphenolic resin.
 25. The curable resin composition set forth in claim 7,wherein component (I) is a mixture of a biphenyl type epoxy resin and aphenol aralkyl type epoxy resin.
 26. The curable resin composition setforth in claim 8, wherein component (I) is a mixture of a biphenyl typeepoxy resin and a phenol aralkyl type epoxy resin.
 27. The curable resincomposition set forth in claim 9, wherein component (I) is a mixture ofa biphenyl type epoxy resin and a phenol aralkyl type epoxy resin. 28.The curable resin composition set forth in claim 7, wherein not lessthan 10 mol % of R¹ in component (II) comprises phenyl groups.
 29. Thecurable resin composition set forth in claim 8, wherein not less than 10mol % of R¹ in component (II) comprises phenyl groups.
 30. The curableresin composition set forth in claim 9, wherein not less than 10 mol %of R¹ in component (II) comprises phenyl groups.
 31. The curable resincomposition set forth in claim 10, wherein not less than 10 mol % of R¹in component (II) comprises phenyl groups.
 32. The curable resincomposition set forth in claim 7, wherein the viscosity of component(III) at 25° C. is 5 to 100,000 mPa·s.
 33. The curable resin compositionset forth in claim 8, wherein the viscosity of component (III) at 25° C.is 5 to 100,000 mPa·s.
 34. The curable resin composition set forth inclaim 9, wherein the viscosity of component (III) at 25° C. is 5 to100,000 mPa·s.
 35. The curable resin composition set forth in claim 10,wherein the viscosity of component (III) at 25° C. is 5 to 100,000mPa·s.
 36. The curable resin composition set forth in claim 11, whereinthe viscosity of component (III) at 25° C. is 5 to 100,000 mPa·s. 37.The curable resin composition set forth in claim 7, wherein the amountof component (II) is 0.1 to 500 parts by weight and that of component(III) is 0.15 to 200 parts by weight per 100 parts by weight ofcomponent (I).
 38. The curable resin composition set forth in claim 8,wherein the amount of component (II) is 0.1 to 500 parts by weight andthat of component (III) is 0.15 to 200 parts by weight per 100 parts byweight of component (I).
 39. The curable resin composition set forth inclaim 9, wherein the amount of component (II) is 0.1 to 500 parts byweight and that of component (III) is 0.15 to 200 parts by weight per100 parts by weight of component (I).
 40. The curable resin compositionset forth in claim 10, wherein the amount of component (II) is 0.1 to500 parts by weight and that of component (III) is 0.15 to 200 parts byweight per 100 parts by weight of component (I).
 41. The curable resincomposition set forth in claim 11, wherein the amount of component (II)is 0.1 to 500 parts by weight and that of component (III) is 0.15 to 200parts by weight per 100 parts by weight of component (I).
 42. Thecurable resin composition set forth in claim 12, wherein the amount ofcomponent (II) is 0.1 to 500 parts by weight and that of component (III)is 0.15 to 200 parts by weight per 100 parts by weight of component (I).43. The curable resin composition set forth in claim 13, wherein theamount of component (II) is 0.1 to 500 parts by weight and that ofcomponent (III) is 0.15 to 200 parts by weight per 100 parts by weightof component (I).
 44. A cured resin obtained by curing the curable resincomposition according to claim
 7. 45. A cured resin obtained by curingthe curable resin composition according to claim
 8. 46. A cured resinobtained by curing the curable resin composition according to claim 9.47. A cured resin obtained by curing the curable resin compositionaccording to claim
 10. 48. A cured resin obtained by curing the curableresin composition according to claim
 11. 49. A cured resin obtained bycuring the curable resin composition according to claim
 12. 50. A curedresin obtained by curing the curable resin composition according toclaim
 13. 51. A cured resin obtained by curing the curable resincomposition according to claim
 14. 52. The curable resin composition setforth in claim 7, wherein component (III) is a silicone resinrepresented by average unit formula (R¹SiO_(3/2))_(a)(R²₂SiO_(2/2))_(b)(R³ ₃SiO_(1/2))_(c)(SiO_(4/2))_(d)(XO_(1/2))_(e), whereR¹, R², and R³ stand for identical or different monovalent hydrocarbongroups or epoxy-containing organic groups, X is a hydrogen atom or alkylgroup, a is a positive number, b is 0 or a positive number, c is 0 or apositive number, d is 0 or a positive number, and e is 0 or a positivenumber such that b/a is a number from 0 to 10, c/a is a number from 0 to0.5, d/(a+b+c+d) is a number from 0 to 0.3, and e/(a+b+c+d) is a numberfrom 0 to
 1. 53. The curable resin composition set forth in claim 8,wherein component (III) is a silicone resin represented by average unitformula (R¹SiO_(3/2))_(a)(R² ₂SiO_(2/2))_(b)(R³₃SiO_(1/2))_(c)(SiO_(4/2))_(d)(XO_(1/2))_(e), where R¹, R², and R³ standfor identical or different monovalent hydrocarbon groups orepoxy-containing organic groups, X is a hydrogen atom or alkyl group, ais a positive number, b is 0 or a positive number, c is 0 or a positivenumber, d is 0 or a positive number, and e is 0 or a positive numbersuch that b/a is a number from 0 to 10, c/a is a number from 0 to 0.5,d/(a+b+c+d) is a number from 0 to 0.3, and e/(a+b+c+d) is a number from0 to
 1. 54. The curable resin composition set forth in claim 9, whereincomponent (III) is a silicone resin represented by average unit formula(R¹SiO_(3/2))_(a)(R² ₂SiO_(2/2))_(b)(R³₃SiO_(1/2))_(c)(SiO_(4/2))_(d)(XO_(1/2))_(e), where R¹, R², and R³ standfor identical or different monovalent hydrocarbon groups orepoxy-containing organic groups, X is a hydrogen atom or alkyl group, ais a positive number, b is 0 or a positive number, c is 0 or a positivenumber, d is 0 or a positive number, and e is 0 or a positive numbersuch that b/a is a number from 0 to 10, c/a is a number from 0 to 0.5,d/(a+b+c+d) is a number from 0 to 0.3, and e/(a+b+c+d) is a number from0 to
 1. 55. The curable resin composition set forth in claim 10, whereincomponent (III) is a silicone resin represented by average unit formula(R¹SiO_(3/2))_(a)(R² ₂SiO_(2/2))_(b)(R³₃SiO_(1/2))_(c)(SiO_(4/2))_(d)(XO_(1/2))_(e), where R¹, R², and R³ standfor identical or different monovalent hydrocarbon groups orepoxy-containing organic groups, X is a hydrogen atom or alkyl group, ais a positive number, b is 0 or a positive number, c is 0 or a positivenumber, d is 0 or a positive number, and e is 0 or a positive numbersuch that b/a is a number from 0 to 10, c/a is a number from 0 to 0.5,d/(a+b+c+d) is a number from 0 to 0.3, and e/(a+b+c+d) is a number from0 to
 1. 56. The curable resin composition set forth in claim 11, whereincomponent (III) is a silicone resin represented by average unit formula(R¹SiO_(3/2))_(a)(R² ₂SiO_(2/2))_(b)(R³₃SiO_(1/2))_(c)(SiO_(4/2))_(d)(XO_(1/2))_(e), where R¹, R², and R³ standfor identical or different monovalent hydrocarbon groups orepoxy-containing organic groups, X is a hydrogen atom or alkyl group, ais a positive number, b is 0 or a positive number, c is 0 or a positivenumber, d is 0 or a positive number, and e is 0 or a positive numbersuch that b/a is a number from 0 to 10, c/a is a number from 0 to 0.5,d/(a+b+c+d) is a number from 0 to 0.3, and e/(a+b+c+d) is a number from0 to
 1. 57. The curable resin composition set forth in claim 12, whereincomponent (III) is a silicone resin represented by average unit formula(R¹SiO_(3/2))_(a)(R² ₂SiO_(2/2))_(b)(R³₃SiO_(1/2))_(c)(SiO_(4/2))_(d)(XO_(1/2))_(e), where R¹, R², and R³ standfor identical or different monovalent hydrocarbon groups orepoxy-containing organic groups, X is a hydrogen atom or alkyl group, ais a positive number, b is 0 or a positive number, c is 0 or a positivenumber, d is 0 or a positive number, and e is 0 or a positive numbersuch that b/a is a number from 0 to 10, c/a is a number from 0 to 0.5,d/(a+b+c+d) is a number from 0 to 0.3, and e/(a+b+c+d) is a number from0 to 1.